7907725

Simple Universal Hash for Plaintext Aware Encryption

PublishedMarch 15, 2011
Assigneenot available in USPTO data we have
Technical Abstract

Patent Claims
24 claims

Legal claims defining the scope of protection, as filed with the USPTO.

1

1. A method for generating a simple universal hash value, the method comprising: configuring at least one processor to perform the steps of functions: inputting at least one of a plurality of Plaintext blocks into an integrity aware encryption scheme using at least one of two secret keys to obtain a plurality of Ciphertext blocks; computing a Plaintext checksum value from the plurality of Plaintext blocks; dividing at least one of the plurality of Ciphertext blocks into a plurality of equal sized segments; assigning each one of a plurality of bits from a third key to each of the plurality of segments, respectively; selecting a single bit from an assigned segment in correspondence with the plurality of bits of the third key; concatenating a plurality of single bits selected from each of the segments to obtain a partial Ciphertext; combining partial Ciphertexts to obtain a Ciphertext checksum; and combining the Plaintext checksum and the Ciphertext checksum to obtain the simple universal hash value.

2

2. The method as defined in claim 1 wherein the Plaintext checksum, the Ciphertext checksum and the universal hash value are all of the same size.

3

3. The method as defined in claim 1 wherein the size of the first of the plurality of Plaintext blocks is a multiple of the size of the universal hash value.

4

4. The method as defined in claim 1 , further comprising computing a partial sum by taking the exclusive-or sum of the plurality of Plaintext blocks and reducing the partial sum to obtain the Plaintext checksum.

5

5. The method as defined in claim 4 wherein reducing the partial sum comprises computation of the exclusive-or sum of equal sized segments of the partial sum.

6

6. The method as defined in claim 1 , further comprising: reducing the plurality of Plaintext blocks to obtain a plurality of partial Plaintext blocks; and combining the plurality of partial Plaintext blocks using an exclusive-or sum to obtain the Plaintext checksum.

7

7. The method as defined in claim 6 wherein reducing the plurality of Plaintext blocks comprises the computation of the exclusive-or sum of equal sized segments of the Plaintext blocks.

8

8. The method as defined in claim 1 wherein obtaining the Ciphertext checksum comprises: selecting partial Ciphertexts using the third key from each of the plurality of Ciphertext blocks; and combining the partial Ciphertexts using an exclusive-or sum to obtain the Ciphertext checksum.

9

9. The method as defined in claim 8 wherein selecting partial Ciphertexts using the third key from a Ciphertext block comprises the process of using the bits of the third key as an index into the Ciphertext block.

10

10. The method as defined in claim 1 wherein the partial Ciphertexts are combined using an exclusive-or sum.

11

11. The method as defined in claim 1 wherein the Plaintext checksum and the Ciphertext checksum are combined by an exclusive-or operation to obtain the universal hash value.

12

12. The method as defined in claim 1 wherein obtaining the Ciphertext checksum comprises: obtaining partial checksums using known universal hash functions from the third key and each of the plurality of Ciphertext blocks; and combining the partial checksums using an exclusive-or sum to obtain the Ciphertext checksum.

13

13. A simple universal hashing apparatus comprising: input means for inputting at least one of a plurality of Plaintext blocks into an integrity aware encryption scheme using at least one of two secret keys to obtain a plurality of Ciphertext blocks; Plaintext checksum means for computing a Plaintext checksum value from said plurality of Plaintext blocks; Ciphertext checksum means for processing said plurality of Ciphertext blocks and a third key to obtain a Ciphertext checksum; and combination means for combining said Plaintext checksum and said Ciphertext checksum to obtain the simple universal hash value, wherein: at least one of said plurality of Ciphertext blocks is divided into a plurality of equal sized segments; each one of a plurality of bits of a third key is assigned to each of the plurality of segments, respectively; the plurality of bits of the third key are used to select a single bit from the assigned segment; a plurality of single bits selected from each of the segments is concatenated to obtain a partial Ciphertext; and partial Ciphertexts are combined to obtain the Ciphertext checksum.

14

14. The apparatus as defined in claim 13 wherein the Plaintext checksum, the Ciphertext checksum and the universal hash value are each of the same size.

15

15. The apparatus as defined in claim 13 wherein the size of the first of the plurality of Plaintext blocks is a multiple of the size of the universal hash value.

16

16. The apparatus as defined in claim 13 , further comprising Plaintext checksum means for computing a partial sum by taking the exclusive-or sum of the plurality of Plaintext blocks and reducing the partial sum to obtain the Plaintext checksum.

17

17. The apparatus as defined in claim 16 wherein the Plaintext checksum means reduces the partial sum by computation of the exclusive-or sum of equal sized segments of the partial sum.

18

18. The apparatus as defined in claim 13 wherein the plurality of Plaintext blocks is reduced to obtain a plurality of partial Plaintext blocks, which, in turn, are combined using an exclusive-or sum to obtain the Plaintext checksum.

19

19. The apparatus as defined in claim 18 wherein the plurality of Plaintext blocks is reduced by computation of the exclusive-or sum of equal sized segments of the Plaintext blocks.

20

20. The apparatus as defined in claim 13 , further comprising means for obtaining the Ciphertext checksum by selecting partial Ciphertexts using the third key from each of the plurality of Ciphertext blocks, and combining the partial Ciphertexts using an exclusive-or sum to obtain the Ciphertext checksum.

21

21. The apparatus as defined in claim 20 wherein the selection of a partial Ciphertext using the third key from a Ciphertext block includes using the bits of the third key as an index into the Ciphertext block.

22

22. The apparatus as defined in claim 13 wherein the partial Ciphertexts are combined using an exclusive-or sum.

23

23. The apparatus as defined in claim 13 , further comprising an exclusive-or unit for combining the Plaintext checksum and the Ciphertext checksum to obtain the universal hash value.

24

24. A non-transitory program storage memory readable by machine, tangibly embodying a program of instructions executable by the machine to perform program steps for generating a simple universal hash value, the program steps comprising: inputting a plurality of Plaintext blocks into an integrity aware encryption scheme using at least one of two secret keys to obtain a corresponding plurality of Ciphertext blocks; computing a Plaintext checksum value responsive to each of said plurality of Plaintext blocks; dividing at least one of the plurality of Ciphertext blocks into a plurality of equal sized segments; assigning each one of a plurality of bits from a third key to each of the plurality of segments, respectively; selecting a single bit from an assigned segment in correspondence with the plurality of bits of the third key; and concatenating a plurality of single bits selected from each of the segments to obtain a partial Ciphertext; combining partial Ciphertexts using an exclusive-or sum to obtain a Ciphertext checksum; and combining said Plaintext checksum and said Ciphertext checksum to obtain the simple universal hash value.

Patent Metadata

Filing Date

Unknown

Publication Date

March 15, 2011

Inventors

William Eric Hall
Charanjit Singh Jutla

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Cite as: Patentable. “SIMPLE UNIVERSAL HASH FOR PLAINTEXT AWARE ENCRYPTION” (7907725). https://patentable.app/patents/7907725

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